The present invention relates to a safety binding for ski.
A safety binding is already known which comprises a monobloc jaw in which one end of the sole of a ski boot engages and is held, this jaw or the support of the jaw being applied, under the action of an elastic mechanism, against two lateral lines of support disposed respectively on either side of the longitudinal plane of symmetry perpendicular to the ski and converging at a point located above the ski. These two lines of support are formed on a support means fixed to the ski and extending substantially vertically inside a housing formed in the monobloc assembly constituted by the jaw and a casing of the binding. One of the opposite transverse faces of the jaw end of the support means presents recessed portions and the other presents projecting members which are housed in said recessed portions and which thus materialise the lines of support which, see in the axis of the ski, converge towards a point located above this ski. In this way, the jaw may pivot either on one of the lines of support or on the other.
In a binding of this type, the jaw or an intermediate piece is located on one side of the support means and is applied against the rear face thereof, whilst the elastic mechanism is housed on the other side of the support means, in the casing of the binding fast with the jaw. This elastic mechanism comprises a mobile member applied under pressure against the front face of the support means, under the action of an elastic member abutting on the casing, so as to apply the jaw elastically on the support means.
In a particular embodiment of such a safety binding, forming the subject matter of French Application for Certificate of Addition No. 78 08342 filed Mar. 22, 1978, the fixed support means presents, on its front face, at least two lines of reaction converging towards the ski and on which the elastically urged member is applied under pressure in the course of a movement of disconnection. The two lines of reaction are disposed so that, for a position of the binding spaced apart from the central retaining or rest position, the line of support of the monobloc assembly constituted by the jaw and the casing of the binding and the line of reaction on which the elastically urged member is applied under pressure, are located on either side of the longitudinal plane of symmetry perpendicular to the ski.
Although such a known safety binding has particularly advantageous features as far as the holding of the boot during the lateral disconnection movement is concerned, it presents the drawback that the support means, which is the element of resistance of the binding, must be moulded or machined so as to present on its front face the two convergent lines of reaction. This results in that the cost price of such a support means and consequently of the binding is relatively high. Furthermore, in the course of a lateral disconnection movement, the leverage of the effort exerted by the elastically urged member decreases regularly so that the return moment of the binding due to this effort decreases very substantially after a certain disconnection stroke. This result is that the return of the jaw of the boot into normal or rest position is difficult to effect as the return mement is relatively low.